Electric power distribution system



March .25, 1952 J. F. ATKINSON ETAL 2,590,083

ELECTRIC POWER DISTRIBUTION SYSTEM Filed Sept. 14.,l 1949 4 Sheets-Sheetl 2? Wr-r:

l: p 85 87 IH' 86 INVENTORS J.F.ATK|NsoN J.'M.MccUTCHEN /34 L 654'4626H.w.KELLr-:Y

-Hgh Voltage/4 I7/ BY ATTORNEY March 25, 1952 Filed Sept. 14, 1949 J. F.ATKINSON ETAL ELECTRIC POWER DISTRIBUTION SYSTEM 4 Sheets-Sheet 2INVENTORS J. F. ATKINSON J.M.MCGUTCHEN .W.KELLEY -BY l i4/617ML),

ATTORNEY March 25, 1952 J F ATKINSON Em 2,590,083

ELEcIRIc POWER DISTRIBUTION SYSTEM Filed sept. 14. 1949 57 *1 INVENTORS58 5 Y i-'ATKINSON f* Ir' J.M.McCUTCHEN H.w.KE| LEY @y BY 2 4,

8 ATTORNEY 'March 25, 1952 J. F. ATKINSON ErAL W ELECTRIC POWERDISTRIBUTION sfsTEM 4 sheen-sheet 4 Filed Sept. 14. 1949 INVENTORS J.F.ATKI NSON ATTORNEY Patented Mar. 25, 1952 ELECTRIC POWER DISTRIBUTIONSYSTEM John F. Atkinson, Harold W. Kelley, and James M. McCutchen,Arlington, Va.

Application September 14, 1949, Serial No. 115,754

(.Granted under the act of March 3, 1883, as

'l' Claims.

amended April 30,' 1928; 370 O. G. 757) This application is made underthe act of March 3, 1883, as amended by the act of April 30, 1928, andthe invention herein described, if patented in any country, may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes throughout the world without thepayment to us of any royalty thereon.

This invention relates to an electric power distribution system.Generally such a system has a power supply, such as a generating plantor subl station, and has a circuit interrupter. Such circuit interrupterprovides an interrupter switch in the hot side of the system, whichusually is operated automatically due to overload, as occurs in case ofa short circuit, to disconnect the portion of the circuit beyond theinterrupter from the power supply.

After repair of the fault, the system is reenergized by closing thecircuit interrupter switch. At times, if the system is heavily loaded,as for example in early evening and when it has been out an appreciablelength of time to eiect the repair, the actual starting loadJ due toturned-on lights, refrigerators, heaters, and so forth, is beyond thedisconnect load of the circuit interrupter. In this circumstance, it isdinicult or even impossible to close the interrupter switch and tomaintain it closed without removal of part of the load from the system.This may require that linemen disconnect part or parts of the system andre-establish connections at intervals after closing of the interrupterswitch thus to energize the system in successive portions. Such apractice is expensive and time consuming', especially in extensivesystems such as occur in rural electrication, and is of considerableinconvenience to consumers because of the dalays in re-establishingservice.

In general, according to the present invention, at least two switchesare connected in such a system in series with each other and with thepower supply, power loads being connected to the portions of the systembetween the switches and beyond the switch which is the more remote fromthe power supply. 'One cf these two switches may be the interrupterswitch, and any number of additional switches may be used. Switchopening means, which operates automatically as a result of zero voltagein the system, as occurs for example upon opening of the interrupterswitch, is provided to open the more remote switch. This sectionalizesthe system. With one switch in addition to the interrupter switch as anexample of a simple installation, the system is sectionalized into aportion between the interrupter switch and additional switch and aportion beyond the additional switch.

Preferably, the switch-opening means is so constructed as to open theswitch it controls a selected interval of time after establishment ofthe zero voltage; that is, with a time lag, the zero voltage usuallybeing established due to opening of the interrupter switch. This timelag prevents opening of the more remote switch due to momentary or zerovoltages of short duration, that is, of a duration shorter than theselected interval required for opening the more remote switch. Theinterval selected will depend, of course, on conditions. If, forexample, the system is operating normally under a light load, so that anoutage of three minutes, say, will not result in a suicient number ofturn-ons of heaters, refrigerators, and so forth, to cause overload uponclosing of the interrupter switch, the selected interval of time lag maybe three minutes. y

Switch-closing means, which operates automatically as a result ofre-established voltage in that portion of the system between theswitches due to closing of the switch less remote from the power supply,is also provided to close the more remote switch. It is essential thatthe switch closing means be so constructed as to operate a selectedinterval of time after closing of the less remote or interrupter switchso that the voltage will be re-established in the portion of the systembeyond the more remote switch with a time lag corresponding to theselected interval after its re-establishment in the portion between theswitches.

The interval selected for this purpose will also depend on conditions.If, for example, the Various portions of the system are heavily loaded,a greater time lag will be required.

With the present system, it is possible easily to locate a system shortcircuit as being in any particular portion of the system. To explainthis, assume a system provided with two switches in addition to theinterrupter switch in series and a third additional switch in parallelwith the sec-v ond (i. e., controlling a branch). Assume the time lagfor closing the three additional switches to be set at l minute, 2minutes and 3 minutes, respectively. If now while the additionalswitches are all open, the interrupter switch is closed, it will beautomatically thrown open at the time the particular additional switchcloses, which controls the portion of the system having the shortcircuit. At 3 minutes, for example, the short circuit would be in theportion controlled by the switch set at 2 minutes. Thus, by setting thetime intervals for closing the additional switches so that each portionof the system will be thrown in at a known interval after closing theinterrupter switch, no two intervals being alike, to locate a short itis merely necessary to compare the time between closing of theinterrupter switch and its automatic opening with the various knowntimes required to throw in any portion of the system.

For a detail description of the invention, reierence is made to theaccompanying drawing, in which- Figure 1 is a diagram of the powerdistribution system employing an interrupter switch and three additionalswitches;

Figure 2 is a schematic showing of One of the additional switches andits switch opening and closing means;

Figure 3 is a side elevation with the casing broken away of a unitcomprising a suitable main switch and switch opening and closing meanstherefor.

Figure 4 is a similar side elevation of the saine unit a quadrantdisplaced from the View of Figure 3;

Figure 5 is a section on line 5-5 of Figure lO;

Figure 6 is a detail VView on line 6-6 of Figure 4;

Figure 7 is a section online '1 -'l of Figure 6;

Figure 8v is Aasection on line 8--8 of Figure 3;

Figure 9 is a section on line 9-9 of Figure S; and

'Figure l0 is a section on line lB--i of Fieure 6.

Referring to Figure l, l5 represents a substation supplying powerthrough a neutral I3 and high voltage line Il. The representation is ofa two-wire system, but the figure as well represents one circuit of amultiphase system. The circuit interrupter is represented at I8,interrupter switch I9 being shown in the hot or high voltage line I1 ofthe system.

Three similar additional switches are shown at 2U, 2| and 22. Branchcircuits or loads 23 and 24 are shown connected in the -portion of thesystem between the switch I9 and the more remote switch V2li, loads 25and 23 in the portion between switch 2.6 and more remote switch 2i andwhich are controlled by switch 2t, loads 2 and 28 in the portion beyondswitch 2i and controlled thereby, and loads 29 and 30 in the portionbeyond switch 22 and controlled thereby, the latter switch being inparallel with switch 2 I.

The opening and closing means for the various additional switches aredesigned in the particular installation represented, to operate on a 110v. supply. Therefore, a transformer is illustrated at 33 for switch 20to reduce the high voltage to the required 110 v. across the neutral 35iand line 35. A special transformer need not be provided for thispurpose, since it is convenient to locate the switch near a pointalready having a 110 v. supply, as for example, on the same Vpole with ausual transformer for reducing the high voltage to consumer, or 110 v.,and in this sense 33 may represent such a transformer.

Figure 2 is representative of switch V and its opening and closingmeans. Assume that the system is in operation. The setting will then beas illustrated. Switch 2B is normally held closed by latch 4B engagingover plunger 4l attached to resilient switch blade 42. Current from the110 v. hot line 35 flows through switch blade 53, contact 44and'conductor 45 through solenoid d and to ground. This operates brake Mto hold shoe i8 engaging brake drum l5 thus to prevent movement of geartrain 59.

If interrupter switch I9 opens, thus to establish zero voltages in thesystem, the solenoid i6 is de-energized and spring 5I of brake d?releases the brake. Spring 5d of spring motor 55, which is normallywound up and prevented from operating by brake 4l, then runs downcausing crank arm 53 to move to the left as viewed in Figure 2. Agovernor such as a fixed friction drum 5l, shoes 58 thrown outwardlyagainst the drum by centrifugal force and pulled inwardly by governorsprings E9, controls the speed of the spring motor, the speed beingdetermined by the tension of the governor springs and power of themotor. Movement of crank arm 53 moves the latch d. The speed of movementof the latch depends on the speed of the spring motor and on theeffective lengthof the crank arm. This effective length is madeadjustable as by means of crank pin 63 operating in slot 6l andadjustable relative to the crank arm.` Thus, the interval of Ytimerequired to unlatch the latch may be selected by proper choice oradjustment of the controlling factors. As the latch moves to the left,springpressed detent 63 nally clears plunger 4|. Spring 64 biased toopen the switch thereupon raises switch blade Q2 from contacts 85 and 66thus to open the main switch 20.

The system is then out of operation and sectionalized. In this sett-ing,spring 'I0 forces switch blade 43 onto contact li. Assume now thatvoltage is re-established as by closing of interrupter switch I9.Current from re-energized line 35 will then flow through blade 43,contact forming a motor switch, and conductor 12, operating constantspeed electric motor T3, and to ground. The motor connects to the geartrain 5i) through clutch 1E, which engages automatically when the motorstarts, and operates to wind the spring motor and move latch 4! to theright as lviewedin Figure 2. As the latch moves, detent 63 bears againstplunger Lil and spring 'I6 is biased. Meanwhile, blade 'J8 ofsolenoid-disconnecting switch 79 is in contact with contact. When thelatch has moved suiliciently far to the right to set it in operativeposition to latch the switch closed, lug 8l operates to move blade 43olf contactv 1|, thus to disconnect the motor, and onto contact 14,forming a solenoid-connecting switch. Current will then ow throughconductor 85, solenoid S3, conductor 8l, blade 18, contact 86 andY toground. This current is established by movement of blade 43 to contactd, and the solenoid quickly forces the main switch blade42 resilientlyinto contact with contacts 65 and 66. When this occurs, detent :S3slips'over the end of the plunger .l. This allows blade 'I3 to open itssolenoiddisconnecting switch due to action of spring 90, thus todisconnect the solenoid from the circuit. Due to the fact that thesolenoid disconnection is controlled by the movement of thedetent 63,the solenoid does not disconnect until the detent has moved over the endof plunger M, that is, after the latch is in position to hold the switchclosed, thus to lock closedblade Vi2 of the main switch. Current lnowflows fromy conductor 35 only through solenoid 46 to hold brake shoe 48in engagement with the drum 49, thus to prevent unwinding of the springmotor, andthesetting is again that illustrated in Figure 2 with thesystem in operation. f

In the particular unit herein illustrated',V only two adjustments areused, motor 13 being ofY a xed constant speed type and the tension ofthegovernor springs 59 and related parts being constant. The time intervalrequired to open the main switch is therefore determined by the speed oflatch 46 with unwinding of the spring motor. Adjustment of the eiectivelength of crank arm 56 by setting of crank pin 6D determines thisinterval within the range of adjustment. Overall variation can beobtained by resetting the governor or using a different speed springmotor.

An adjustable stop 95 provides the second adjustment. This adjusts thedistance the latch 40 may be moved to the left (Figure 2) after openingof the main switch and consequently the distance the latch must be movedto the right by operation of the constant speed motor before the mainswitch automatically closes. The time interval required for totalmovement of the latch to the right is selected by proper setting of stop95.

The unit including the main switch and its switch opening and closingmeans, structurally illustrated in Figures 4 through 10, has partsessentially corresponding to those described above relative to thediagrammatic showing, and these essential parts have been given the samecharacters throughout.

Referring now to the structural showing, the unit shown includes a,housing Hic, preferably oil lled, with a removable cover it! on whichthe parts are mounted. The main switch terminals |02 and |03 are wiredin through insulators IM and |65 of conventional type.

The hot side of the 110 v. line for operating the switch opening andclosing means is wired in through insulator |56, the ground side beingconnected directly to the casing which is in turn connected to theneutral of the line by means of lug |01.

The contacts 65 and G of the main switch are supported on an insulatingstrip |08 which is in turn supported by pillars |69 and H0 nxed to across piece to which is attached an upright tube ||2 bolted to thecasing top as illustrated. Plunger 4| operates in tube ||2 and solenoid88 surrounds the tube.

The electric motor 13 is of conventional construction and is of the typewhich automatically throws clutch plate ||5 into proper engagement whenthe motor is energized. The gear train 50 comprises a speed reductionsystem as best illustrated in Figure 6, one gear I i6 being the springmotor gear and driving the screw ||1 and worm gear I8, the latter beingin effect the crank arm 56 previously mentioned.

Switch parts 43, 44, 'is and 'H previously described are structurallycombined forming a conventional type snap action 2-way switch shown atin Figure 8.

The solenoid disconnecting switch schematically illustrated at 'i9 isstructurally illustrated in Figure 6 as a conventional mercury type tiltswitch, tilted to open the switch when detent 63 is in position lockingthe main switch closed.

We claim:

1. In an electric power distribution system provided with a powersupply, at least two switches connected in the system in series witheach other and with the power supply, power loads connected to theportion of the system between the switches and beyond the switch moreremote from the power supply, switch-opening means operatingautomatically as a result of zero voltage in the system to open the moreremote switch, and switch-closing means operating automatically as aresult of re-established voltage in that portion of the system betweenthe switches due to closing of the switch less remote from the powersupply to close the more remote switch, said switchclosing means beingconstructed to operate a selected interval of time after closing of theless remote switch, thus to re-establish the voltage in the systembeyond the more remote switch a selected interval of time after itsre-establishment in that portion between the switches.

2. The electric power distribution system as dened in claim l,characterized in that the less remote switch is an interrupter switchWhich operates automatically due to overload to disconnect the portionof the system beyond it from the power supply.

3. The electric power distribution system as dened in claim 1,characterized in that the switch opening means is constructed to openthe more remote switch a selected interval of time after establishmentof the zero voltage thus to prevent opening of the more remote switchdue to a zero voltage of a shorter duration than the selected intervalrequired for opening the more remote switch.

4. The electric power distribution system as defined in claim 3,characterized in that the switch-opening means includes a spring biasedto open the more remote switch, a latch which normally holds the moreremote switch closed against the bias of the spring, a spring motorwhich runs down to unlatch the latch, and a brake for preventingoperation of the spring motor, said brake being normally held applied asa result of voltage in the system and being released upon establishmentof the zero voltage.

5. The electric power distribution system as dened in claim 4,characterized in that switchclosing means includes an electric motorenergized by the re-established voltage to wind the spring motor and setthe latch in operative position to latch the more remote switch closed,and a solenoid energized by the re-established voltage to close the moreremote switch, said solenoid being connected into the re-establishedvoltage by a solenoid-connecting switch operated by the motor a selectedinterval of time after the motor is energized and being disconnectedfrom the re-established voltage by a solenoid-disconnecting switchoperated by the latch to cause the disconnection after the latch is inposition to hold the more remote switch closed.

6. In an electric power distribution system provided with a powersupply, an interrupter switch connected in the system in series with thepower supply, a plurality of additional switches connected in the systemin series with each other and with the interrupter switch, and powerloads connected to the portions of the system between the switches, eachadditional switch having switch-opening means operated automatically asa result of zero voltage in the system due to opening of the interrupterswitch to open its switch and having switch-closing means operatedautomatically as a result of re-established voltage in the portion ofthe system between it and the next switch less remote from the powersupply to close its switch, said switch-closing means being constructedto operate a selected interval of time after re-establishment of thevoltage, whereby upon re-establishment of the voltage due to closing theinterrupter switch the switch-'closing means operate to close theadditional switches in succession thus to re-establish the voltagesuccessively in the portions of the system between the switches withtime-interval lags between reestablishments corresponding to theselected REFERENCES CITEDk intervals of time of the switch-closingmeans. The following references are of record in the 7.' The electricpower distribution system as me of this patent: defined in claim 6,characterized in that each switch-opening means is constructed` to openits 5 UNITED STATES PATENTS switch a selected interval of time afterestablish- Number Name Date ment of the zero voltage thus to preventopening 2,231,052 Bryson Feb. l1, 1941 of the additional-switches due toa zero voltage 2,240,656 Lindstrom May 6, 1941 of shorter duration thanthe selected interval 2,333,459 Atwoodv Nov. 2, 1943 required foropening the additional switches. 1n 2,445,836 McCrosky July 27, 1948JOHN F. ATKINSON. HAROLD W. KELLEY. JAMES M ,MCCUTCHEN

